Jruby on Rails not picking up java heap parameters properly

Question

I'm running Jruby on Rails on Tomcat in windows, also using sidekiq for running background jobs. When I try to import large CSV files I got the dreaded heap error.

So I tried setting JAVA_OPTS

set JAVA_OPTS = -Xmx8192m -Xms8192m -Xmn4096m

and I started to get heap errors inconsistently.

Tried _JAVA_OPTIONS

set _JAVA_OPTIONS = -Xmx8192m -Xms8192m -Xmn4096m

and it picked up the new heap values; problem solved.

After this I tried running

java -XX:+PrintFlagsFinal -version | grep HeapSize

$ java -XX:+PrintFlagsFinal -version | grep HeapSize
    uintx ErgoHeapSizeLimit                         = 0               {product}

    uintx HeapSizePerGCThread                       = 87241520        {product}

    uintx InitialHeapSize                          := 805102400       {product}

    uintx LargePageHeapSizeThreshold                = 134217728       {product}

    uintx MaxHeapSize                              := 4292870144      {product}

java version "1.7.0_79"
Java(TM) SE Runtime Environment (build 1.7.0_79-b15)
Java HotSpot(TM) 64-Bit Server VM (build 24.79-b02, mixed mode)

Why is the MaxHeapSize value greater than initial when I set both as the same?

viprasant viprasant · Accepted Answer · 2017-04-16T08:04:18

It should be

set _JAVA_OPTIONS=-Xmx8192m -Xms8192m -Xmn4096m

instead of

set _JAVA_OPTIONS = -Xmx8192m -Xms8192m -Xmn4096m

There should not be any space on either side of the equal sign.

Jruby on Rails not picking up java heap parameters properly

1 Answers